This invention relates primarily to oilfield pipelines, although it is not limited to this particular field. Most oilfield pipelines employ tubular members constructed of steel and is usually referred to as seamless pressure tubing, line pipe, or standard tubing. There are many different ways in which the tubular members are joined to one another to effect a continuous fluid conducting pipeline of limitless length.
In the prior art, it is known to join tubular members by threadedly connecting the ends together by employment of tapered threaded connections which rely upon friction for a sealed fit. Repeated expansion and contraction of the pipeline has a deleterious effect upon this method of construction and ultimately causes the threads to stretch until leakage occurs at the threaded connections.
There is another widely used method of connecting tubular members together by the joining of two beveled opposed ends of pipe joints in a butt welded manner. However, the cost of labor and equipment required for this method is enormous.
Still others have proposed joining lengths of steel tubular goods together by a number of other different means, including the employment of grooved ends having gaskets and bolted couplers; the use of crimping tools; the application of interlocking tabs; as well as the use of o-rings and compression rings.
For example, Veitch, U.S. Pat. No. 2,498,831 connects plastic pipe together with a coupling member, and uses an adhesive as a sealing means between the marginal pipe end and the coupling member.
Reesor, U.S. Pat. No. 3,343,252 joins conduit together by employment of a knurling process along with an interlocking crimping process.
Curtin, U.S. Pat. No. 3,971,574 teaches that plastic pipe may be joined with a smooth fitted coupler, and includes an outside locking coupler.
Kyle, et al, U.S. Pat. No. 1,919,734; Carter U.S. Pat. No. 4,014,568; Bartholomew U.S. Pat. 3,997,195; Streit U.S. Pat. 4,002,358; Lowe U.S. Pat. No. 4,026,584; Asano U.S. Pat. No. 4,043,574; Martinez U.S. Pat. No. 4,076,285; Ramm U.S. Pat. No. 3,633,943; McGuire U.S. Pat. No. 3,701,548; Bingham U.S. Pat. No. 3,807,776; Frey U.S. Pat. No. 4,067,534; Wise U.S. Pat. No. 3,843,169; Garrett U.S. Pat. No. 3,565,468; and Singer U.S. Pat. No. 2,967,067 are other examples of the multitude of approaches to the problem of forming a continuous fluid conveying conduit from a plurality of pipe joints.
The closest art known to the present invention is applicant's previous U.S. Pat. Nos. 4,328,608 and 4,328,983; to which reference is made for further background of this invention.
The present invention constitutes a step forward over the above mentioned prior art by providing a fast, reliable, and inexpensive method and apparatus by which tubular goods are connected together into a continuous fluid conveying pipeline.